Funds provided by the NCRR Grant 1C06RR7400-01 have facilitated the build out of the seventh floor shell space in the MCN II Animal Facility. This new space will provide housing for an additional 10,000 cages of mice and for expansion of the Transgenic Mouse/ES Cell Shared Resource. This growth is essential for the continued success of the research enterprise at Vanderbilt University (VU). For three years, the mouse census has increased by 2000 cages annually; currently the actual mouse census is ahead of the July 2003 projections. To accommodate the expanding mouse population, additional ventilated cage and rack units must be purchased. Compared to a static system, ventilated cage and rack units offer the advantage of housing a larger number of mouse cages in the same floor space. This application requests funding to purchase 25 single sided and 12 double-sided ventilated cage and rack units. VU is committed to converting all housing of mice to ventilated cage and rack units. These ventilated cages will ease the overcrowding in other existing animal facilities, improve the microenvironment of the mice, and reduce personnel exposure to mouse allergens. The research programs of 57 PHS funded investigators will directly benefit from the availability of these ventilated units. Many investigators (including the 57 mentioned above) utilize germ-line altered mice in their research. The Transgenic Mouse and ES Cell Shared Resource has been instrumental in providing services to produce and maintain these unique mouse strains. Expansion of the services offered by this resource will be enhanced by the availability of additional equipment. Funding is requested to purchase two Vertical Flow Stations, two Taylor Wharton Liquid Nitrogen small tank dewars, two roller bases for dewars, two low level battery alarms, a Xenoworks Automatic Transjector with Manipulators, and a Labconco Freeze Dry System. This equipment is important to VU's continuing effort to provide new services such as Intracytoplasmic Sperm Injection (ICSI) and maintain the cryopreservation of sperm and embryos.